Fertilizers and nutrients often cannot be applied to the foliage or leaf system of plants and trees, a delivery route termed foliar fertilization, because of damage that would occur to the plant or leaf. Various chemical compounds or by-products associated with conventional fertilizer compositions will often burn or otherwise damage a plant leaf upon direct contact.
Conventional fertilizers must be applied to the roots or growing medium, and typically are associated with admonitions to avoid application to or contact with the plant foliage. For example, calcium oxide and zinc dihydrate will burn plant leaves upon direct foliar application.